A variety of medical devices are used for chronic, i.e., long-term, delivery of therapy to patients suffering from a variety of conditions, such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, spasticity, or gastroparesis. Pumps or other medical fluid delivery devices may be used for chronic delivery of therapeutic agents, such as drugs. Typically, such fluid delivery devices provide therapy continuously or periodically according to parameters contained within a program. A program may comprise respective values for each of a plurality of parameters, specified by a clinician. The fluid delivery devices may be implantable medical devices that receive the program from a programmer controlled by the clinician.
Implantable fluid delivery devices are intended to provide a patient with a therapeutic output to alleviate or assist with a variety of conditions. Typically, such devices provide a therapeutic output under specified conditions on a recurring basis. One type of implantable fluid delivery device is a drug infusion device which can deliver a fluid medication to a patient at a selected site. A drug infusion device may be implanted at a location in the body of a patient and deliver a fluid medication through one or more catheters to a selected delivery site in the body. Drug infusion devices, such as implantable drug pumps, include fluid reservoirs that may be self-sealing and may be accessible through ports. A drug infusion device may be configured to deliver a therapeutic agent from the fluid reservoir to a patient according to a therapy program, which may, for example, specify a rate of delivery by the IMD of a fluid delivered to the patient.